Digital still image capturing devices typically capture light with an electronic image sensor in order to capture an image. The captured image is stored in a memory. A typical digital image may range in size from about 20 kilobytes to about 4 megabytes, depending on the image resolution and the image compression algorithm being used. However, a memory of an image capturing device can store only a limited amount of images. Memory capacity is therefore a concern in digital still image capturing devices.
The prior art approaches the memory problem by typically including an internal image memory, a removable memory medium, or sometimes both. A user can address memory limitations by managing (i.e., selectively and periodically deleting) the images in the camera. Alternatively, the user may buy additional memory media in order to avoid a memory shortage. Managing the images in the camera may include deleting images and/or transferring images to an external device for storage. After they have been transferred, the user can delete the images from the camera's memory and take more images.
However, there are several drawbacks in memory use in the prior art. If the internal memory becomes filled up, the user cannot take any more pictures. The user must then manually delete images even if the user had previously copied images out of the internal memory and archived them on another device. Worse, if the user is at a location where it is not possible to transfer internally stored images to another storage device, the user will not be able to take any more pictures unless some stored images are deleted (without having been saved in another device). This places a burden on the user, who may be distracted from the process of setting up a shot in order to check the memory and to transfer and/or delete images.
In another prior art approach, some prior art cameras delete all images that are transferred from the internal memory. This is done in order to maintain the largest amount of available memory. As a result, these images are no longer available to the camera for review, sharing (i.e., showing to friends via the camera-back display), or further downloading to printers or other computer devices. In this prior art approach, the user must pay more attention to the downloading process, as the user can only download an image once. If the user accidentally deletes an image, it is gone. The user cannot transfer it out of the camera again.
Therefore, there remains a need in the art for improvements in memory management in image capturing devices.